This invention relates to code translation and, more particularly, to the translation of signals from a first binary code to a second binary code and vice versa.
Binary code representation of information signals is now well known in the art. Two codes which have experienced widespread use are the so-called conventional binary code, now commonly referred to as binary code, and the reflected binary code, now commonly referred to as Gray code.
Uses and advantages of both the binary and Gray codes are well known and it has become common to convert or translate between these codes in order to realize efficiencies in communications systems. The conversion of signals from the Gray (G) code to binary (B) code is expressed EQU B.sub.0 = G.sub.0 ( 1)
and EQU B.sub.N = G.sub.N .sym. B.sub.N-1 for N .gtoreq. 1, (2)
where 0 represents the most significant bit and as N increases the bit is less significant, and the conversion of signals from the binary code to the Gray code is expressed EQU G.sub.0 = B.sub.0 ( 3)
and EQU G.sub.N = B.sub.N .sym. B.sub.N-1 for N .gtoreq. 1, (4)
where 0 is the most significant bit and as N increases the bit is less significant.
FIG. 1 shows a table illustrating the relationship between binary code, Gray code and the corresponding decimal number. It will be apparent from the tabulation shown in FIG. 1 how any number may be determined in either the binary code or the Gray code.
A number of arrangements have been developed for translating signals from one code to the other. In light of the Exclusive OR functional relationship between the codes, as indicated in Equations 1 through 4, it has become common practice to employ digital logic circuit arragements including Exclusive OR gates to implement the desired translation functions. In certain applications, however, it is undesirable to employ such digital logic circuits because they are fairly complex and usually require the use of precise bias potentials and levels other than those readily available. This is especially true in equipment which primarily employs analog circuit elements, for example, differential amplifiers and the like. Since use of digital logic circuits usually requires additional power supplies, such use is undesirable from both an economic standpoint and a space usage standpoint.